1. Field of the Invention
The present invention relates to a vehicle door latch device, and more specifically, relates to a latch device provided with a self-canceling mechanism which is capable of restoring a vehicle door (latch device) from a locked state to an unlocked state so as to prevent the door from being unintentionally locked, when closing the door. The self-canceling mechanism is also used as a mechanism composing a part of a one-motion mechanism which is capable of opening the door and restoring the latch device from the locked state to the unlocked state at the same time when an interior opening handle of the door is operated during the locked state.
2. Description of the Related Art
Referring to FIGS. 10 and 11, a conventional vehicle door latch device comprises: a ratchet A for holding an engagement between a latch and a striker; an outer open lever C connected to an exterior opening handle B of a door; a lock lever D switching the latch device between a locked state and an unlocked state; an open link E provided between the open lever C and the lock lever D; a ratchet lever (self-cancel lever) F connected to the ratchet A; an inner open lever H rotated by an interior opening handle G of the door; and a horizontal raised portion J formed on a latch body or housing of the latch device and receiving the striker when closing the door. The open link E is displaced, in FIG. 11, between a locked position shown in a solid line near the center of the latch body and an unlocked position shown in a dotted line a little approaching the exterior side of the latch body by the rotation of the lock lever D. The link E has a first bent portion L which is engageably opposed to a projection K of the self-canceling lever F when the link E is in the unlocked position. The inner open lever H indirectly has a second bent portion M which is engageably opposed to the projection K. The self-canceling lever F has a tip end P which is engageably opposed to a third bent portion N formed on the open link E.
When closing the door in the locked state, the ratchet A is rotated by the contact with the latch to rotate the self-canceling lever F counterclockwise in FIG. 11, and the tip end P of the self-canceling lever F then comes into contact with the third bent portion N of the open link E and pushes the link E toward the exterior side of the latch body. Thereby, the latch device is restored from the locked state to the unlocked state before the door is completely closed. This is a self-canceling mechanism of the latch device.
Further, when the interior opening handle G is operated to open the door in the door closed and locked states, the second bent portion M comes into contact with the projection K of the self-canceling lever F through the inner open lever H to rotate the self-canceling lever F counterclockwise in FIG. 11. Consequently, the ratchet A which is connected to the lever F is moved and separated from the latch so as to open the door. At the same time, the open link E is restored to the unlocked position by the contact with the tip end P of the self-canceling lever F, as mentioned above. This is a one-motion mechanism of the latch device.
A problem to be solved of the conventional latch device is in that the open link E is extending from the open lever C to the lock lever D over the horizontal raised portion J formed on the latch body, so that the link E and the raised portion J are overlapped, thus creating a problem of increased thickness of the latch device.
On the other hand, U.S. Pat. No. 5,181,754 discloses another latch device which solves the above problem by locating an open link (33) to an exterior side of a horizontal raised portion (13). In this latch device, the open link (33) is displaced into the locked position when it is substantially shifted to the exterior side of the latch body (1). This is an opposite structure of the former prior art latch device shown in FIGS. 10 and 11. The reason why the locked position and the unlocked position of the open link are opposite, is to make it possible to provide the open link on the exterior side of the raised portion without increasing the width of the latch body. If the unlocked position of the open link (33) is made to be on the exterior side of the locked position, the position of the pin (10) which is equivalent to the projection K of the former prior art should be also moved to the exterior side, so that the width of the latch body is increased. Because of such a difference in arrangement, it becomes impossible to use the self-canceling lever used in the former latch device, in the latter latch device. Therefore, the latter latch device has adopted a key-less-lock mechanism having the same object as the self-canceling mechanism, but since there is a difference in the operating method between the key-less-lock mechanism and the self-canceling mechanism, confusion has been given to the user in some cases.